April Fools (a long time ago)
The best April Fools prank I can remember was when my father was cooking himself some breakfast, standing at the stove, and my mother shrieked, "There's an EAGLE in the back yard!!"
He leaped in the air, did a 180° turn, and reached out with both hands as if he had pulled a pair of pistols. So, the eagle thing . . they have actually returned to this area now, but at that time they were locally extinct. It wasn't 100% impossible, though, that one had gotten off course or just decided to re-settle in the area. Improbable, but not impossible.
No one, including him, could figure out why he had pulled imaginary six-shooters. Was he picturing the eagle carrying off the livestock? Attacking the patio door? Engaging him in a Wild West duel? It was forever a mystery.